Colitag™ Presence/Absence (P/A) Water Test Kit For Total Coliforms ...

Colitag Presence/Absence (P/A) Water Test Kit
For Total Coliforms and E. coli
Product Overview Colitag is a selective and differential medium for the
determination of the presence or absence of total coliforms and E. coli in drinking
water. It is a one-step, ready to use medium, to be combined with a water
sample. This product is designed to test water samples for coliform and/or E. coli
bacteria in 24 ± 2 hours and does not require further confirmation or verification
steps. Colitag detects 1 colony-forming unit (CFU) of E. coli and other coliform
bacteria in 100mL of water.
Method Summary A 100-mL water sample is mixed with Colitag TM followed by
incubation at 35.0º C ± 0.5º C for 24 ± 2 hours. If coliform bacteria are present,
the medium changes color from near colorless to yellow. In addition, if any E. coli
bacteria are present in the sample, a bright blue fluorescence is emitted when
the sample is subjected to long wavelength (366-nanometer) ultraviolet (UV) light
placed 3-4 centimeters away.
The Colitag TM method is based on the detection of two enzymes, ß-
glucuronidase and ß-galactosidase, which are characteristic of E. coli and the
coliform groups, respectively. Colitag TM detects Total Coliforms using the
chromogenic substrate ortho-nitrophenyl-ß-D-galactopyranoside (ONPG). Upon
hydrolysis by ß-galactosidase, ONPG produces a distinct yellow color, confirming
the presence of coliforms in the sample. For detection of E. coli, Colitag
utilizes the fluorogenic enzyme substrate 4-methylumbelliferyl-ß-D-glucuronide
(MUG). Upon hydrolysis by ß-glucuronidase, MUG releases 4-
methylumbelliferone. This reaction by-product fluoresces when exposed to UV
light. The ß-glucuronidase enzyme is specific to E. coli and observation of
fluorescence differentiates this organism from other members of the coliform
group.
Only the Colitag method offers a patented technology called “acid resuscitation”
for increased test sensitivity. In this cutting edge technology, a small amount of
acid works together with specialized nutrients to resuscitate weak and injured E.
coli and other coliform cells.

Test Procedure for Total Coliforms and MUG-Positive E. coli Bacteria
1. Aseptically add Colitag to a 100-mL test water sample. Agitate to begin
dissolution. *Note: the solution can be a pale straw-like color. This is due to the
rich nutrients in the medium. Distinct color change to yellow indicates a positive
sample.
2. Incubate the sample and medium mixture at 35.0º C ± 0.5º C for 24 ± 2 hours.
Sample Interpretation
1. Visually check each sample for yellow color. If the test sample is yellow then
coliform bacteria are present. If no yellow color is observed, the sample should
be recorded as negative for coliform bacteria.
2. Examine the solution for fluorescence using a long wavelength (366 nm) UV
lamp. If bright blue fluorescence is observed, E. coli bacteria are present. If no
fluorescence is observed, the sample should be recorded as negative for E. coli.
Product Storage Store at 4°C to 30°C, away from light.
The Material Safety Data Sheet for Colitag is available upon request or by
visiting us on-line at:
www.cpiinternational.com or,
www.colitag.com
Revised: November 2005
CPI International • 5580 Skylane Blvd. • Santa Rosa, CA • 95403 • ph (800) 878-
7654 or (707) 525-5788 #335 • fax (707) 545-7901